Nanofiber Paper for Fuel Cells and Catalyst Supports

A dramatic improvement in hydrogen fuel cell cathode performance will be needed before the technology can be considered viable and used to create a hydrogen economy. The use of carbon nanotubes as catalyst supports could produce outstanding leaps in performance and catalyst utilization, but three problems are associated with their use: (1) cost and availability, (2) no simple manufacturing method for making a practical product, and (3) its smooth basal plane surface (which provides few anchoring points for binding catalyst particles). The latter problem requires that the nanotubes be pitted or abraded using strong oxidants, in order to generate features that foster a well-dispersed catalyst distribution). This project will solve all three problems with an inexpensive ($100/lb) nanofiber that is well-suited for catalyst binding. The nanofiber will be processed into a catalyst support using a straightforward, wet-laid papermaking procedure that is ideal for continuous manufacturing. In previous work, the nanofiber was modified with special surface chemistry that promotes catalyst activity. In initial testing, a cathode made with a thin nanofiber layer exhibited over three times the catalyst utilization compared to state-of-the-art procecures. Phase I will concentrate on the cathode only, defining the best combination of nanofiber layer thickness, composition, and ionomer content. Phase II will involve both electrodes and continuous manufacturing. Commercial Applications and other Benefits as described by the awardee: Fuel-cell-related applications for this technology include conventional hydrogen PEM cells, cells that work above 100 degrees C, methanol fuel cells, and also water electrolysis or ammonia electrolysis for producing hydrogen. The ability to tailor the product¿s composition with additives will enable applications such as catalyst supports, composites, electromagnetic shielding, lithium-ion anodes, and electrochemical capacitors. The nanofiber¿s low cost and bulk availability should make it practical to pursue continuous papermaking.